Improve the readability of log --graph output

index f53135485f..c56fdec1fc 100644
@@ -115,11 +115,20 @@ static const char *column_get_color_code(unsigned short color)
 static void strbuf_write_column(struct strbuf *sb, const struct column *c,
 				char col_char)
 {
+	/*
+	 * Remember the buffer's width as we're about to add non-printing
+	 * content to it, and we want to avoid counting the byte length
+	 * of this content towards the buffer's visible width
+	 */
+	size_t prev_width = sb->width;
+
 	if (c->color < column_colors_max)
 		strbuf_addstr(sb, column_get_color_code(c->color));
 	strbuf_addch(sb, col_char);
 	if (c->color < column_colors_max)
 		strbuf_addstr(sb, column_get_color_code(column_colors_max));
+
+	sb->width = prev_width + 1;
 }
 
 struct git_graph {

@@ -686,8 +695,7 @@ static int graph_is_mapping_correct(struct git_graph *graph)
 	return 1;
 }
 
-static void graph_pad_horizontally(struct git_graph *graph, struct strbuf *sb,
-				   int chars_written)
+static void graph_pad_horizontally(struct git_graph *graph, struct strbuf *sb)
 {
 	/*
 	 * Add additional spaces to the end of the strbuf, so that all

@@ -696,8 +704,8 @@ static void graph_pad_horizontally(struct git_graph *graph, struct strbuf *sb,
 	 * This way, fields printed to the right of the graph will remain
 	 * aligned for the entire commit.
 	 */
-	if (chars_written < graph->width)
-		strbuf_addchars(sb, ' ', graph->width - chars_written);
+	if (sb->width < graph->width)
+		strbuf_addchars(sb, ' ', graph->width - sb->width);
 }
 
 static void graph_output_padding_line(struct git_graph *graph,

@@ -723,7 +731,7 @@ static void graph_output_padding_line(struct git_graph *graph,
 		strbuf_addch(sb, ' ');
 	}
 
-	graph_pad_horizontally(graph, sb, graph->num_new_columns * 2);
+	graph_pad_horizontally(graph, sb);
 }
 
 

@@ -740,7 +748,7 @@ static void graph_output_skip_line(struct git_graph *graph, struct strbuf *sb)
 	 * of the graph is missing.
 	 */
 	strbuf_addstr(sb, "...");
-	graph_pad_horizontally(graph, sb, 3);
+	graph_pad_horizontally(graph, sb);
 
 	if (graph->num_parents >= 3 &&
 	    graph->commit_index < (graph->num_columns - 1))

@@ -754,7 +762,6 @@ static void graph_output_pre_commit_line(struct git_graph *graph,
 {
 	int num_expansion_rows;
 	int i, seen_this;
-	int chars_written;
 
 	/*
 	 * This function formats a row that increases the space around a commit

@@ -777,14 +784,12 @@ static void graph_output_pre_commit_line(struct git_graph *graph,
 	 * Output the row
 	 */
 	seen_this = 0;
-	chars_written = 0;
 	for (i = 0; i < graph->num_columns; i++) {
 		struct column *col = &graph->columns[i];
 		if (col->commit == graph->commit) {
 			seen_this = 1;
 			strbuf_write_column(sb, col, '|');
 			strbuf_addchars(sb, ' ', graph->expansion_row);
-			chars_written += 1 + graph->expansion_row;
 		} else if (seen_this && (graph->expansion_row == 0)) {
 			/*
 			 * This is the first line of the pre-commit output.

@@ -800,19 +805,15 @@ static void graph_output_pre_commit_line(struct git_graph *graph,
 				strbuf_write_column(sb, col, '\\');
 			else
 				strbuf_write_column(sb, col, '|');
-			chars_written++;
 		} else if (seen_this && (graph->expansion_row > 0)) {
 			strbuf_write_column(sb, col, '\\');
-			chars_written++;
 		} else {
 			strbuf_write_column(sb, col, '|');
-			chars_written++;
 		}
 		strbuf_addch(sb, ' ');
-		chars_written++;
 	}
 
-	graph_pad_horizontally(graph, sb, chars_written);
+	graph_pad_horizontally(graph, sb);
 
 	/*
 	 * Increment graph->expansion_row,

@@ -842,11 +843,9 @@ static void graph_output_commit_char(struct git_graph *graph, struct strbuf *sb)
 }
 
 /*
- * Draw the horizontal dashes of an octopus merge and return the number of
- * characters written.
+ * Draw the horizontal dashes of an octopus merge.
  */
-static int graph_draw_octopus_merge(struct git_graph *graph,
-				    struct strbuf *sb)
+static void graph_draw_octopus_merge(struct git_graph *graph, struct strbuf *sb)
 {
 	/*
 	 * Here dashless_parents represents the number of parents which don't

@@ -890,13 +889,12 @@ static int graph_draw_octopus_merge(struct git_graph *graph,
 		strbuf_write_column(sb, &graph->new_columns[i+first_col],
 				    i == dashful_parents-1 ? '.' : '-');
 	}
-	return 2 * dashful_parents;
 }
 
 static void graph_output_commit_line(struct git_graph *graph, struct strbuf *sb)
 {
 	int seen_this = 0;
-	int i, chars_written;
+	int i;
 
 	/*
 	 * Output the row containing this commit

@@ -906,7 +904,6 @@ static void graph_output_commit_line(struct git_graph *graph, struct strbuf *sb)
 	 * children that we have already processed.)
 	 */
 	seen_this = 0;
-	chars_written = 0;
 	for (i = 0; i <= graph->num_columns; i++) {
 		struct column *col = &graph->columns[i];
 		struct commit *col_commit;

@@ -921,14 +918,11 @@ static void graph_output_commit_line(struct git_graph *graph, struct strbuf *sb)
 		if (col_commit == graph->commit) {
 			seen_this = 1;
 			graph_output_commit_char(graph, sb);
-			chars_written++;
 
 			if (graph->num_parents > 2)
-				chars_written += graph_draw_octopus_merge(graph,
-									  sb);
+				graph_draw_octopus_merge(graph, sb);
 		} else if (seen_this && (graph->num_parents > 2)) {
 			strbuf_write_column(sb, col, '\\');
-			chars_written++;
 		} else if (seen_this && (graph->num_parents == 2)) {
 			/*
 			 * This is a 2-way merge commit.

@@ -948,16 +942,13 @@ static void graph_output_commit_line(struct git_graph *graph, struct strbuf *sb)
 				strbuf_write_column(sb, col, '\\');
 			else
 				strbuf_write_column(sb, col, '|');
-			chars_written++;
 		} else {
 			strbuf_write_column(sb, col, '|');
-			chars_written++;
 		}
 		strbuf_addch(sb, ' ');
-		chars_written++;
 	}
 
-	graph_pad_horizontally(graph, sb, chars_written);
+	graph_pad_horizontally(graph, sb);
 
 	/*
 	 * Update graph->state

@@ -984,12 +975,11 @@ static struct column *find_new_column_by_commit(struct git_graph *graph,
 static void graph_output_post_merge_line(struct git_graph *graph, struct strbuf *sb)
 {
 	int seen_this = 0;
-	int i, j, chars_written;
+	int i, j;
 
 	/*
 	 * Output the post-merge row
 	 */
-	chars_written = 0;
 	for (i = 0; i <= graph->num_columns; i++) {
 		struct column *col = &graph->columns[i];
 		struct commit *col_commit;

@@ -1017,7 +1007,6 @@ static void graph_output_post_merge_line(struct git_graph *graph, struct strbuf
 			assert(par_column);
 
 			strbuf_write_column(sb, par_column, '|');
-			chars_written++;
 			for (j = 0; j < graph->num_parents - 1; j++) {
 				parents = next_interesting_parent(graph, parents);
 				assert(parents);

@@ -1026,19 +1015,16 @@ static void graph_output_post_merge_line(struct git_graph *graph, struct strbuf
 				strbuf_write_column(sb, par_column, '\\');
 				strbuf_addch(sb, ' ');
 			}
-			chars_written += j * 2;
 		} else if (seen_this) {
 			strbuf_write_column(sb, col, '\\');
 			strbuf_addch(sb, ' ');
-			chars_written += 2;
 		} else {
 			strbuf_write_column(sb, col, '|');
 			strbuf_addch(sb, ' ');
-			chars_written += 2;
 		}
 	}
 
-	graph_pad_horizontally(graph, sb, chars_written);
+	graph_pad_horizontally(graph, sb);
 
 	/*
 	 * Update graph->state

@@ -1181,7 +1167,7 @@ static void graph_output_collapsing_line(struct git_graph *graph, struct strbuf
 		}
 	}
 
-	graph_pad_horizontally(graph, sb, graph->mapping_size);
+	graph_pad_horizontally(graph, sb);
 
 	/*
 	 * Swap mapping and new_mapping

@@ -1199,6 +1185,8 @@ static void graph_output_collapsing_line(struct git_graph *graph, struct strbuf
 
 int graph_next_line(struct git_graph *graph, struct strbuf *sb)
 {
+	sb->width = 0;
+
 	switch (graph->state) {
 	case GRAPH_PADDING:
 		graph_output_padding_line(graph, sb);

@@ -1227,7 +1215,6 @@ int graph_next_line(struct git_graph *graph, struct strbuf *sb)
 static void graph_padding_line(struct git_graph *graph, struct strbuf *sb)
 {
 	int i;
-	int chars_written = 0;
 
 	if (graph->state != GRAPH_COMMIT) {
 		graph_next_line(graph, sb);

@@ -1245,19 +1232,16 @@ static void graph_padding_line(struct git_graph *graph, struct strbuf *sb)
 		struct column *col = &graph->columns[i];
 
 		strbuf_write_column(sb, col, '|');
-		chars_written++;
 
 		if (col->commit == graph->commit && graph->num_parents > 2) {
 			int len = (graph->num_parents - 2) * 2;
 			strbuf_addchars(sb, ' ', len);
-			chars_written += len;
 		} else {
 			strbuf_addch(sb, ' ');
-			chars_written++;
 		}
 	}
 
-	graph_pad_horizontally(graph, sb, chars_written);
+	graph_pad_horizontally(graph, sb);
 
 	/*
 	 * Update graph->prev_state since we have output a padding line

index f62278a0be..3a98147321 100644
@@ -66,11 +66,12 @@ struct string_list;
 struct strbuf {
 	size_t alloc;
 	size_t len;
+	size_t width;
 	char *buf;
 };
 
 extern char strbuf_slopbuf[];
-#define STRBUF_INIT  { .alloc = 0, .len = 0, .buf = strbuf_slopbuf }
+#define STRBUF_INIT  { .alloc = 0, .len = 0, .width = 0, .buf = strbuf_slopbuf }
 
 /*
  * Predeclare this here, since cache.h includes this file before it defines the

@@ -161,6 +162,10 @@ static inline void strbuf_setlen(struct strbuf *sb, size_t len)
 {
 	if (len > (sb->alloc ? sb->alloc - 1 : 0))
 		die("BUG: strbuf_setlen() beyond buffer");
+	if (len > sb->len)
+		sb->width += len - sb->len;
+	else
+		sb->width = len;
 	sb->len = len;
 	if (sb->buf != strbuf_slopbuf)
 		sb->buf[len] = '\0';

@@ -231,6 +236,7 @@ static inline void strbuf_addch(struct strbuf *sb, int c)
 		strbuf_grow(sb, 1);
 	sb->buf[sb->len++] = c;
 	sb->buf[sb->len] = '\0';
+	sb->width++;
 }
 
 /**

index f53135485f..24bf1f4fe1 100644
@@ -112,14 +112,38 @@ static const char *column_get_color_code(unsigned short color)
 	return column_colors[color];
 }
 
-static void strbuf_write_column(struct strbuf *sb, const struct column *c,
-				char col_char)
+struct graph_strbuf {
+	struct strbuf *buf;
+	size_t width;
+};
+
+static inline void graph_strbuf_addch(struct graph_strbuf *sb, int c)
+{
+	strbuf_addch(sb->buf, c);
+	sb->width++;
+}
+
+void graph_strbuf_addchars(struct graph_strbuf *sb, int c, size_t n)
+{
+	strbuf_addchars(sb->buf, c, n);
+	sb->width += n;
+}
+
+static inline void graph_strbuf_addstr(struct graph_strbuf *sb, const char *s)
+{
+	strbuf_addstr(sb->buf, s);
+	sb->width += strlen(s);
+}
+
+static void graph_strbuf_write_column(struct graph_strbuf *sb, const struct column *c,
+				      char col_char)
 {
 	if (c->color < column_colors_max)
-		strbuf_addstr(sb, column_get_color_code(c->color));
-	strbuf_addch(sb, col_char);
+		strbuf_addstr(sb->buf, column_get_color_code(c->color));
+	strbuf_addch(sb->buf, col_char);
+	sb->width++;
 	if (c->color < column_colors_max)
-		strbuf_addstr(sb, column_get_color_code(column_colors_max));
+		strbuf_addstr(sb->buf, column_get_color_code(column_colors_max));
 }
 
 struct git_graph {

@@ -686,8 +710,7 @@ static int graph_is_mapping_correct(struct git_graph *graph)
 	return 1;
 }
 
-static void graph_pad_horizontally(struct git_graph *graph, struct strbuf *sb,
-				   int chars_written)
+static void graph_pad_horizontally(struct git_graph *graph, struct graph_strbuf *sb)
 {
 	/*
 	 * Add additional spaces to the end of the strbuf, so that all

@@ -696,12 +719,12 @@ static void graph_pad_horizontally(struct git_graph *graph, struct strbuf *sb,
 	 * This way, fields printed to the right of the graph will remain
 	 * aligned for the entire commit.
 	 */
-	if (chars_written < graph->width)
-		strbuf_addchars(sb, ' ', graph->width - chars_written);
+	if (sb->width < graph->width)
+		strbuf_addchars(sb->buf, ' ', graph->width - sb->width);
 }
 
 static void graph_output_padding_line(struct git_graph *graph,
-				      struct strbuf *sb)
+				      struct graph_strbuf *sb)
 {
 	int i;
 

@@ -719,11 +742,11 @@ static void graph_output_padding_line(struct git_graph *graph,
 	 * Output a padding row, that leaves all branch lines unchanged
 	 */
 	for (i = 0; i < graph->num_new_columns; i++) {
-		strbuf_write_column(sb, &graph->new_columns[i], '|');
-		strbuf_addch(sb, ' ');
+		graph_strbuf_write_column(sb, &graph->new_columns[i], '|');
+		graph_strbuf_addch(sb, ' ');
 	}
 
-	graph_pad_horizontally(graph, sb, graph->num_new_columns * 2);
+	graph_pad_horizontally(graph, sb);
 }
 
 

@@ -733,14 +756,14 @@ int graph_width(struct git_graph *graph)
 }
 
 
-static void graph_output_skip_line(struct git_graph *graph, struct strbuf *sb)
+static void graph_output_skip_line(struct git_graph *graph, struct graph_strbuf *sb)
 {
 	/*
 	 * Output an ellipsis to indicate that a portion
 	 * of the graph is missing.
 	 */
-	strbuf_addstr(sb, "...");
-	graph_pad_horizontally(graph, sb, 3);
+	graph_strbuf_addstr(sb, "...");
+	graph_pad_horizontally(graph, sb);
 
 	if (graph->num_parents >= 3 &&
 	    graph->commit_index < (graph->num_columns - 1))

@@ -750,11 +773,10 @@ static void graph_output_skip_line(struct git_graph *graph, struct strbuf *sb)
 }
 
 static void graph_output_pre_commit_line(struct git_graph *graph,
-					 struct strbuf *sb)
+					 struct graph_strbuf *sb)
 {
 	int num_expansion_rows;
 	int i, seen_this;
-	int chars_written;
 
 	/*
 	 * This function formats a row that increases the space around a commit

@@ -777,14 +799,12 @@ static void graph_output_pre_commit_line(struct git_graph *graph,
 	 * Output the row
 	 */
 	seen_this = 0;
-	chars_written = 0;
 	for (i = 0; i < graph->num_columns; i++) {
 		struct column *col = &graph->columns[i];
 		if (col->commit == graph->commit) {
 			seen_this = 1;
-			strbuf_write_column(sb, col, '|');
-			strbuf_addchars(sb, ' ', graph->expansion_row);
-			chars_written += 1 + graph->expansion_row;
+			graph_strbuf_write_column(sb, col, '|');
+			graph_strbuf_addchars(sb, ' ', graph->expansion_row);
 		} else if (seen_this && (graph->expansion_row == 0)) {
 			/*
 			 * This is the first line of the pre-commit output.

@@ -797,22 +817,18 @@ static void graph_output_pre_commit_line(struct git_graph *graph,
 			 */
 			if (graph->prev_state == GRAPH_POST_MERGE &&
 			    graph->prev_commit_index < i)
-				strbuf_write_column(sb, col, '\\');
+				graph_strbuf_write_column(sb, col, '\\');
 			else
-				strbuf_write_column(sb, col, '|');
-			chars_written++;
+				graph_strbuf_write_column(sb, col, '|');
 		} else if (seen_this && (graph->expansion_row > 0)) {
-			strbuf_write_column(sb, col, '\\');
-			chars_written++;
+			graph_strbuf_write_column(sb, col, '\\');
 		} else {
-			strbuf_write_column(sb, col, '|');
-			chars_written++;
+			graph_strbuf_write_column(sb, col, '|');
 		}
-		strbuf_addch(sb, ' ');
-		chars_written++;
+		graph_strbuf_addch(sb, ' ');
 	}
 
-	graph_pad_horizontally(graph, sb, chars_written);
+	graph_pad_horizontally(graph, sb);
 
 	/*
 	 * Increment graph->expansion_row,

@@ -823,7 +839,7 @@ static void graph_output_pre_commit_line(struct git_graph *graph,
 		graph_update_state(graph, GRAPH_COMMIT);
 }
 
-static void graph_output_commit_char(struct git_graph *graph, struct strbuf *sb)
+static void graph_output_commit_char(struct git_graph *graph, struct graph_strbuf *sb)
 {
 	/*
 	 * For boundary commits, print 'o'

@@ -831,22 +847,20 @@ static void graph_output_commit_char(struct git_graph *graph, struct strbuf *sb)
 	 */
 	if (graph->commit->object.flags & BOUNDARY) {
 		assert(graph->revs->boundary);
-		strbuf_addch(sb, 'o');
+		graph_strbuf_addch(sb, 'o');
 		return;
 	}
 
 	/*
 	 * get_revision_mark() handles all other cases without assert()
 	 */
-	strbuf_addstr(sb, get_revision_mark(graph->revs, graph->commit));
+	graph_strbuf_addstr(sb, get_revision_mark(graph->revs, graph->commit));
 }
 
 /*
- * Draw the horizontal dashes of an octopus merge and return the number of
- * characters written.
+ * Draw the horizontal dashes of an octopus merge.
  */
-static int graph_draw_octopus_merge(struct git_graph *graph,
-				    struct strbuf *sb)
+static void graph_draw_octopus_merge(struct git_graph *graph, struct graph_strbuf *sb)
 {
 	/*
 	 * Here dashless_parents represents the number of parents which don't

@@ -886,17 +900,16 @@ static int graph_draw_octopus_merge(struct git_graph *graph,
 
 	int i;
 	for (i = 0; i < dashful_parents; i++) {
-		strbuf_write_column(sb, &graph->new_columns[i+first_col], '-');
-		strbuf_write_column(sb, &graph->new_columns[i+first_col],
-				    i == dashful_parents-1 ? '.' : '-');
+		graph_strbuf_write_column(sb, &graph->new_columns[i+first_col], '-');
+		graph_strbuf_write_column(sb, &graph->new_columns[i+first_col],
+					  i == dashful_parents-1 ? '.' : '-');
 	}
-	return 2 * dashful_parents;
 }
 
-static void graph_output_commit_line(struct git_graph *graph, struct strbuf *sb)
+static void graph_output_commit_line(struct git_graph *graph, struct graph_strbuf *sb)
 {
 	int seen_this = 0;
-	int i, chars_written;
+	int i;
 
 	/*
 	 * Output the row containing this commit

@@ -906,7 +919,6 @@ static void graph_output_commit_line(struct git_graph *graph, struct strbuf *sb)
 	 * children that we have already processed.)
 	 */
 	seen_this = 0;
-	chars_written = 0;
 	for (i = 0; i <= graph->num_columns; i++) {
 		struct column *col = &graph->columns[i];
 		struct commit *col_commit;

@@ -921,14 +933,11 @@ static void graph_output_commit_line(struct git_graph *graph, struct strbuf *sb)
 		if (col_commit == graph->commit) {
 			seen_this = 1;
 			graph_output_commit_char(graph, sb);
-			chars_written++;
 
 			if (graph->num_parents > 2)
-				chars_written += graph_draw_octopus_merge(graph,
-									  sb);
+				graph_draw_octopus_merge(graph, sb);
 		} else if (seen_this && (graph->num_parents > 2)) {
-			strbuf_write_column(sb, col, '\\');
-			chars_written++;
+			graph_strbuf_write_column(sb, col, '\\');
 		} else if (seen_this && (graph->num_parents == 2)) {
 			/*
 			 * This is a 2-way merge commit.

@@ -945,19 +954,16 @@ static void graph_output_commit_line(struct git_graph *graph, struct strbuf *sb)
 			 */
 			if (graph->prev_state == GRAPH_POST_MERGE &&
 			    graph->prev_commit_index < i)
-				strbuf_write_column(sb, col, '\\');
+				graph_strbuf_write_column(sb, col, '\\');
 			else
-				strbuf_write_column(sb, col, '|');
-			chars_written++;
+				graph_strbuf_write_column(sb, col, '|');
 		} else {
-			strbuf_write_column(sb, col, '|');
-			chars_written++;
+			graph_strbuf_write_column(sb, col, '|');
 		}
-		strbuf_addch(sb, ' ');
-		chars_written++;
+		graph_strbuf_addch(sb, ' ');
 	}
 
-	graph_pad_horizontally(graph, sb, chars_written);
+	graph_pad_horizontally(graph, sb);
 
 	/*
 	 * Update graph->state

@@ -981,15 +987,14 @@ static struct column *find_new_column_by_commit(struct git_graph *graph,
 	return NULL;
 }
 
-static void graph_output_post_merge_line(struct git_graph *graph, struct strbuf *sb)
+static void graph_output_post_merge_line(struct git_graph *graph, struct graph_strbuf *sb)
 {
 	int seen_this = 0;
-	int i, j, chars_written;
+	int i, j;
 
 	/*
 	 * Output the post-merge row
 	 */
-	chars_written = 0;
 	for (i = 0; i <= graph->num_columns; i++) {
 		struct column *col = &graph->columns[i];
 		struct commit *col_commit;

@@ -1016,29 +1021,25 @@ static void graph_output_post_merge_line(struct git_graph *graph, struct strbuf
 			par_column = find_new_column_by_commit(graph, parents->item);
 			assert(par_column);
 
-			strbuf_write_column(sb, par_column, '|');
-			chars_written++;
+			graph_strbuf_write_column(sb, par_column, '|');
 			for (j = 0; j < graph->num_parents - 1; j++) {
 				parents = next_interesting_parent(graph, parents);
 				assert(parents);
 				par_column = find_new_column_by_commit(graph, parents->item);
 				assert(par_column);
-				strbuf_write_column(sb, par_column, '\\');
-				strbuf_addch(sb, ' ');
+				graph_strbuf_write_column(sb, par_column, '\\');
+				graph_strbuf_addch(sb, ' ');
 			}
-			chars_written += j * 2;
 		} else if (seen_this) {
-			strbuf_write_column(sb, col, '\\');
-			strbuf_addch(sb, ' ');
-			chars_written += 2;
+			graph_strbuf_write_column(sb, col, '\\');
+			graph_strbuf_addch(sb, ' ');
 		} else {
-			strbuf_write_column(sb, col, '|');
-			strbuf_addch(sb, ' ');
-			chars_written += 2;
+			graph_strbuf_write_column(sb, col, '|');
+			graph_strbuf_addch(sb, ' ');
 		}
 	}
 
-	graph_pad_horizontally(graph, sb, chars_written);
+	graph_pad_horizontally(graph, sb);
 
 	/*
 	 * Update graph->state

@@ -1049,7 +1050,7 @@ static void graph_output_post_merge_line(struct git_graph *graph, struct strbuf
 		graph_update_state(graph, GRAPH_COLLAPSING);
 }
 
-static void graph_output_collapsing_line(struct git_graph *graph, struct strbuf *sb)
+static void graph_output_collapsing_line(struct git_graph *graph, struct graph_strbuf *sb)
 {
 	int i;
 	short used_horizontal = 0;

@@ -1159,9 +1160,9 @@ static void graph_output_collapsing_line(struct git_graph *graph, struct strbuf
 	for (i = 0; i < graph->mapping_size; i++) {
 		int target = graph->new_mapping[i];
 		if (target < 0)
-			strbuf_addch(sb, ' ');
+			graph_strbuf_addch(sb, ' ');
 		else if (target * 2 == i)
-			strbuf_write_column(sb, &graph->new_columns[target], '|');
+			graph_strbuf_write_column(sb, &graph->new_columns[target], '|');
 		else if (target == horizontal_edge_target &&
 			 i != horizontal_edge - 1) {
 				/*

@@ -1172,16 +1173,16 @@ static void graph_output_collapsing_line(struct git_graph *graph, struct strbuf
 				if (i != (target * 2)+3)
 					graph->new_mapping[i] = -1;
 				used_horizontal = 1;
-			strbuf_write_column(sb, &graph->new_columns[target], '_');
+			graph_strbuf_write_column(sb, &graph->new_columns[target], '_');
 		} else {
 			if (used_horizontal && i < horizontal_edge)
 				graph->new_mapping[i] = -1;
-			strbuf_write_column(sb, &graph->new_columns[target], '/');
+			graph_strbuf_write_column(sb, &graph->new_columns[target], '/');
 
 		}
 	}
 
-	graph_pad_horizontally(graph, sb, graph->mapping_size);
+	graph_pad_horizontally(graph, sb);
 
 	/*
 	 * Swap mapping and new_mapping

@@ -1199,24 +1200,26 @@ static void graph_output_collapsing_line(struct git_graph *graph, struct strbuf
 
 int graph_next_line(struct git_graph *graph, struct strbuf *sb)
 {
+	struct graph_strbuf gsb = { .buf = sb, .width = 0 };
+
 	switch (graph->state) {
 	case GRAPH_PADDING:
-		graph_output_padding_line(graph, sb);
+		graph_output_padding_line(graph, &gsb);
 		return 0;
 	case GRAPH_SKIP:
-		graph_output_skip_line(graph, sb);
+		graph_output_skip_line(graph, &gsb);
 		return 0;
 	case GRAPH_PRE_COMMIT:
-		graph_output_pre_commit_line(graph, sb);
+		graph_output_pre_commit_line(graph, &gsb);
 		return 0;
 	case GRAPH_COMMIT:
-		graph_output_commit_line(graph, sb);
+		graph_output_commit_line(graph, &gsb);
 		return 1;
 	case GRAPH_POST_MERGE:
-		graph_output_post_merge_line(graph, sb);
+		graph_output_post_merge_line(graph, &gsb);
 		return 0;
 	case GRAPH_COLLAPSING:
-		graph_output_collapsing_line(graph, sb);
+		graph_output_collapsing_line(graph, &gsb);
 		return 0;
 	}
 

@@ -1227,7 +1230,7 @@ int graph_next_line(struct git_graph *graph, struct strbuf *sb)
 static void graph_padding_line(struct git_graph *graph, struct strbuf *sb)
 {
 	int i;
-	int chars_written = 0;
+	struct graph_strbuf gsb = { .buf = sb, .width = 0 };
 
 	if (graph->state != GRAPH_COMMIT) {
 		graph_next_line(graph, sb);

@@ -1244,20 +1247,17 @@ static void graph_padding_line(struct git_graph *graph, struct strbuf *sb)
 	for (i = 0; i < graph->num_columns; i++) {
 		struct column *col = &graph->columns[i];
 
-		strbuf_write_column(sb, col, '|');
-		chars_written++;
+		graph_strbuf_write_column(&gsb, col, '|');
 
 		if (col->commit == graph->commit && graph->num_parents > 2) {
 			int len = (graph->num_parents - 2) * 2;
-			strbuf_addchars(sb, ' ', len);
-			chars_written += len;
+			graph_strbuf_addchars(&gsb, ' ', len);
 		} else {
-			strbuf_addch(sb, ' ');
-			chars_written++;
+			graph_strbuf_addch(&gsb, ' ');
 		}
 	}
 
-	graph_pad_horizontally(graph, sb, chars_written);
+	graph_pad_horizontally(graph, &gsb);
 
 	/*
 	 * Update graph->prev_state since we have output a padding line

index f53135485f..2f81a5d23d 100644
@@ -112,14 +112,42 @@ static const char *column_get_color_code(unsigned short color)
 	return column_colors[color];
 }
 
-static void strbuf_write_column(struct strbuf *sb, const struct column *c,
-				char col_char)
+struct graph_line {
+	struct strbuf *buf;
+	size_t width;
+};
+
+static inline void graph_line_addch(struct graph_line *line, int c)
+{
+	strbuf_addch(line->buf, c);
+	line->width++;
+}
+
+static inline void graph_line_addchars(struct graph_line *line, int c, size_t n)
+{
+	strbuf_addchars(line->buf, c, n);
+	line->width += n;
+}
+
+static inline void graph_line_addstr(struct graph_line *line, const char *s)
+{
+	strbuf_addstr(line->buf, s);
+	line->width += strlen(s);
+}
+
+static inline void graph_line_addcolor(struct graph_line *line, unsigned short color)
+{
+	strbuf_addstr(line->buf, column_get_color_code(color));
+}
+
+static void graph_line_write_column(struct graph_line *line, const struct column *c,
+				    char col_char)
 {
 	if (c->color < column_colors_max)
-		strbuf_addstr(sb, column_get_color_code(c->color));
-	strbuf_addch(sb, col_char);
+		graph_line_addcolor(line, c->color);
+	graph_line_addch(line, col_char);
 	if (c->color < column_colors_max)
-		strbuf_addstr(sb, column_get_color_code(column_colors_max));
+		graph_line_addcolor(line, column_colors_max);
 }
 
 struct git_graph {

@@ -686,8 +714,7 @@ static int graph_is_mapping_correct(struct git_graph *graph)
 	return 1;
 }
 
-static void graph_pad_horizontally(struct git_graph *graph, struct strbuf *sb,
-				   int chars_written)
+static void graph_pad_horizontally(struct git_graph *graph, struct graph_line *line)
 {
 	/*
 	 * Add additional spaces to the end of the strbuf, so that all

@@ -696,12 +723,12 @@ static void graph_pad_horizontally(struct git_graph *graph, struct strbuf *sb,
 	 * This way, fields printed to the right of the graph will remain
 	 * aligned for the entire commit.
 	 */
-	if (chars_written < graph->width)
-		strbuf_addchars(sb, ' ', graph->width - chars_written);
+	if (line->width < graph->width)
+		graph_line_addchars(line, ' ', graph->width - line->width);
 }
 
 static void graph_output_padding_line(struct git_graph *graph,
-				      struct strbuf *sb)
+				      struct graph_line *line)
 {
 	int i;
 

@@ -719,11 +746,11 @@ static void graph_output_padding_line(struct git_graph *graph,
 	 * Output a padding row, that leaves all branch lines unchanged
 	 */
 	for (i = 0; i < graph->num_new_columns; i++) {
-		strbuf_write_column(sb, &graph->new_columns[i], '|');
-		strbuf_addch(sb, ' ');
+		graph_line_write_column(line, &graph->new_columns[i], '|');
+		graph_line_addch(line, ' ');
 	}
 
-	graph_pad_horizontally(graph, sb, graph->num_new_columns * 2);
+	graph_pad_horizontally(graph, line);
 }
 
 

@@ -733,14 +760,14 @@ int graph_width(struct git_graph *graph)
 }
 
 
-static void graph_output_skip_line(struct git_graph *graph, struct strbuf *sb)
+static void graph_output_skip_line(struct git_graph *graph, struct graph_line *line)
 {
 	/*
 	 * Output an ellipsis to indicate that a portion
 	 * of the graph is missing.
 	 */
-	strbuf_addstr(sb, "...");
-	graph_pad_horizontally(graph, sb, 3);
+	graph_line_addstr(line, "...");
+	graph_pad_horizontally(graph, line);
 
 	if (graph->num_parents >= 3 &&
 	    graph->commit_index < (graph->num_columns - 1))

@@ -750,11 +777,10 @@ static void graph_output_skip_line(struct git_graph *graph, struct strbuf *sb)
 }
 
 static void graph_output_pre_commit_line(struct git_graph *graph,
-					 struct strbuf *sb)
+					 struct graph_line *line)
 {
 	int num_expansion_rows;
 	int i, seen_this;
-	int chars_written;
 
 	/*
 	 * This function formats a row that increases the space around a commit

@@ -777,14 +803,12 @@ static void graph_output_pre_commit_line(struct git_graph *graph,
 	 * Output the row
 	 */
 	seen_this = 0;
-	chars_written = 0;
 	for (i = 0; i < graph->num_columns; i++) {
 		struct column *col = &graph->columns[i];
 		if (col->commit == graph->commit) {
 			seen_this = 1;
-			strbuf_write_column(sb, col, '|');
-			strbuf_addchars(sb, ' ', graph->expansion_row);
-			chars_written += 1 + graph->expansion_row;
+			graph_line_write_column(line, col, '|');
+			graph_line_addchars(line, ' ', graph->expansion_row);
 		} else if (seen_this && (graph->expansion_row == 0)) {
 			/*
 			 * This is the first line of the pre-commit output.

@@ -797,22 +821,18 @@ static void graph_output_pre_commit_line(struct git_graph *graph,
 			 */
 			if (graph->prev_state == GRAPH_POST_MERGE &&
 			    graph->prev_commit_index < i)
-				strbuf_write_column(sb, col, '\\');
+				graph_line_write_column(line, col, '\\');
 			else
-				strbuf_write_column(sb, col, '|');
-			chars_written++;
+				graph_line_write_column(line, col, '|');
 		} else if (seen_this && (graph->expansion_row > 0)) {
-			strbuf_write_column(sb, col, '\\');
-			chars_written++;
+			graph_line_write_column(line, col, '\\');
 		} else {
-			strbuf_write_column(sb, col, '|');
-			chars_written++;
+			graph_line_write_column(line, col, '|');
 		}
-		strbuf_addch(sb, ' ');
-		chars_written++;
+		graph_line_addch(line, ' ');
 	}
 
-	graph_pad_horizontally(graph, sb, chars_written);
+	graph_pad_horizontally(graph, line);
 
 	/*
 	 * Increment graph->expansion_row,

@@ -823,7 +843,7 @@ static void graph_output_pre_commit_line(struct git_graph *graph,
 		graph_update_state(graph, GRAPH_COMMIT);
 }
 
-static void graph_output_commit_char(struct git_graph *graph, struct strbuf *sb)
+static void graph_output_commit_char(struct git_graph *graph, struct graph_line *line)
 {
 	/*
 	 * For boundary commits, print 'o'

@@ -831,22 +851,20 @@ static void graph_output_commit_char(struct git_graph *graph, struct strbuf *sb)
 	 */
 	if (graph->commit->object.flags & BOUNDARY) {
 		assert(graph->revs->boundary);
-		strbuf_addch(sb, 'o');
+		graph_line_addch(line, 'o');
 		return;
 	}
 
 	/*
 	 * get_revision_mark() handles all other cases without assert()
 	 */
-	strbuf_addstr(sb, get_revision_mark(graph->revs, graph->commit));
+	graph_line_addstr(line, get_revision_mark(graph->revs, graph->commit));
 }
 
 /*
- * Draw the horizontal dashes of an octopus merge and return the number of
- * characters written.
+ * Draw the horizontal dashes of an octopus merge.
  */
-static int graph_draw_octopus_merge(struct git_graph *graph,
-				    struct strbuf *sb)
+static void graph_draw_octopus_merge(struct git_graph *graph, struct graph_line *line)
 {
 	/*
 	 * Here dashless_parents represents the number of parents which don't

@@ -886,17 +904,16 @@ static int graph_draw_octopus_merge(struct git_graph *graph,
 
 	int i;
 	for (i = 0; i < dashful_parents; i++) {
-		strbuf_write_column(sb, &graph->new_columns[i+first_col], '-');
-		strbuf_write_column(sb, &graph->new_columns[i+first_col],
-				    i == dashful_parents-1 ? '.' : '-');
+		graph_line_write_column(line, &graph->new_columns[i+first_col], '-');
+		graph_line_write_column(line, &graph->new_columns[i+first_col],
+					  i == dashful_parents-1 ? '.' : '-');
 	}
-	return 2 * dashful_parents;
 }
 
-static void graph_output_commit_line(struct git_graph *graph, struct strbuf *sb)
+static void graph_output_commit_line(struct git_graph *graph, struct graph_line *line)
 {
 	int seen_this = 0;
-	int i, chars_written;
+	int i;
 
 	/*
 	 * Output the row containing this commit

@@ -906,7 +923,6 @@ static void graph_output_commit_line(struct git_graph *graph, struct strbuf *sb)
 	 * children that we have already processed.)
 	 */
 	seen_this = 0;
-	chars_written = 0;
 	for (i = 0; i <= graph->num_columns; i++) {
 		struct column *col = &graph->columns[i];
 		struct commit *col_commit;

@@ -920,15 +936,12 @@ static void graph_output_commit_line(struct git_graph *graph, struct strbuf *sb)
 
 		if (col_commit == graph->commit) {
 			seen_this = 1;
-			graph_output_commit_char(graph, sb);
-			chars_written++;
+			graph_output_commit_char(graph, line);
 
 			if (graph->num_parents > 2)
-				chars_written += graph_draw_octopus_merge(graph,
-									  sb);
+				graph_draw_octopus_merge(graph, line);
 		} else if (seen_this && (graph->num_parents > 2)) {
-			strbuf_write_column(sb, col, '\\');
-			chars_written++;
+			graph_line_write_column(line, col, '\\');
 		} else if (seen_this && (graph->num_parents == 2)) {
 			/*
 			 * This is a 2-way merge commit.

@@ -945,19 +958,16 @@ static void graph_output_commit_line(struct git_graph *graph, struct strbuf *sb)
 			 */
 			if (graph->prev_state == GRAPH_POST_MERGE &&
 			    graph->prev_commit_index < i)
-				strbuf_write_column(sb, col, '\\');
+				graph_line_write_column(line, col, '\\');
 			else
-				strbuf_write_column(sb, col, '|');
-			chars_written++;
+				graph_line_write_column(line, col, '|');
 		} else {
-			strbuf_write_column(sb, col, '|');
-			chars_written++;
+			graph_line_write_column(line, col, '|');
 		}
-		strbuf_addch(sb, ' ');
-		chars_written++;
+		graph_line_addch(line, ' ');
 	}
 
-	graph_pad_horizontally(graph, sb, chars_written);
+	graph_pad_horizontally(graph, line);
 
 	/*
 	 * Update graph->state

@@ -981,15 +991,14 @@ static struct column *find_new_column_by_commit(struct git_graph *graph,
 	return NULL;
 }
 
-static void graph_output_post_merge_line(struct git_graph *graph, struct strbuf *sb)
+static void graph_output_post_merge_line(struct git_graph *graph, struct graph_line *line)
 {
 	int seen_this = 0;
-	int i, j, chars_written;
+	int i, j;
 
 	/*
 	 * Output the post-merge row
 	 */
-	chars_written = 0;
 	for (i = 0; i <= graph->num_columns; i++) {
 		struct column *col = &graph->columns[i];
 		struct commit *col_commit;

@@ -1016,29 +1025,25 @@ static void graph_output_post_merge_line(struct git_graph *graph, struct strbuf
 			par_column = find_new_column_by_commit(graph, parents->item);
 			assert(par_column);
 
-			strbuf_write_column(sb, par_column, '|');
-			chars_written++;
+			graph_line_write_column(line, par_column, '|');
 			for (j = 0; j < graph->num_parents - 1; j++) {
 				parents = next_interesting_parent(graph, parents);
 				assert(parents);
 				par_column = find_new_column_by_commit(graph, parents->item);
 				assert(par_column);
-				strbuf_write_column(sb, par_column, '\\');
-				strbuf_addch(sb, ' ');
+				graph_line_write_column(line, par_column, '\\');
+				graph_line_addch(line, ' ');
 			}
-			chars_written += j * 2;
 		} else if (seen_this) {
-			strbuf_write_column(sb, col, '\\');
-			strbuf_addch(sb, ' ');
-			chars_written += 2;
+			graph_line_write_column(line, col, '\\');
+			graph_line_addch(line, ' ');
 		} else {
-			strbuf_write_column(sb, col, '|');
-			strbuf_addch(sb, ' ');
-			chars_written += 2;
+			graph_line_write_column(line, col, '|');
+			graph_line_addch(line, ' ');
 		}
 	}
 
-	graph_pad_horizontally(graph, sb, chars_written);
+	graph_pad_horizontally(graph, line);
 
 	/*
 	 * Update graph->state

@@ -1049,7 +1054,7 @@ static void graph_output_post_merge_line(struct git_graph *graph, struct strbuf
 		graph_update_state(graph, GRAPH_COLLAPSING);
 }
 
-static void graph_output_collapsing_line(struct git_graph *graph, struct strbuf *sb)
+static void graph_output_collapsing_line(struct git_graph *graph, struct graph_line *line)
 {
 	int i;
 	short used_horizontal = 0;

@@ -1159,9 +1164,9 @@ static void graph_output_collapsing_line(struct git_graph *graph, struct strbuf
 	for (i = 0; i < graph->mapping_size; i++) {
 		int target = graph->new_mapping[i];
 		if (target < 0)
-			strbuf_addch(sb, ' ');
+			graph_line_addch(line, ' ');
 		else if (target * 2 == i)
-			strbuf_write_column(sb, &graph->new_columns[target], '|');
+			graph_line_write_column(line, &graph->new_columns[target], '|');
 		else if (target == horizontal_edge_target &&
 			 i != horizontal_edge - 1) {
 				/*

@@ -1172,16 +1177,16 @@ static void graph_output_collapsing_line(struct git_graph *graph, struct strbuf
 				if (i != (target * 2)+3)
 					graph->new_mapping[i] = -1;
 				used_horizontal = 1;
-			strbuf_write_column(sb, &graph->new_columns[target], '_');
+			graph_line_write_column(line, &graph->new_columns[target], '_');
 		} else {
 			if (used_horizontal && i < horizontal_edge)
 				graph->new_mapping[i] = -1;
-			strbuf_write_column(sb, &graph->new_columns[target], '/');
+			graph_line_write_column(line, &graph->new_columns[target], '/');
 
 		}
 	}
 
-	graph_pad_horizontally(graph, sb, graph->mapping_size);
+	graph_pad_horizontally(graph, line);
 
 	/*
 	 * Swap mapping and new_mapping

@@ -1199,24 +1204,26 @@ static void graph_output_collapsing_line(struct git_graph *graph, struct strbuf
 
 int graph_next_line(struct git_graph *graph, struct strbuf *sb)
 {
+	struct graph_line line = { .buf = sb, .width = 0 };
+
 	switch (graph->state) {
 	case GRAPH_PADDING:
-		graph_output_padding_line(graph, sb);
+		graph_output_padding_line(graph, &line);
 		return 0;
 	case GRAPH_SKIP:
-		graph_output_skip_line(graph, sb);
+		graph_output_skip_line(graph, &line);
 		return 0;
 	case GRAPH_PRE_COMMIT:
-		graph_output_pre_commit_line(graph, sb);
+		graph_output_pre_commit_line(graph, &line);
 		return 0;
 	case GRAPH_COMMIT:
-		graph_output_commit_line(graph, sb);
+		graph_output_commit_line(graph, &line);
 		return 1;
 	case GRAPH_POST_MERGE:
-		graph_output_post_merge_line(graph, sb);
+		graph_output_post_merge_line(graph, &line);
 		return 0;
 	case GRAPH_COLLAPSING:
-		graph_output_collapsing_line(graph, sb);
+		graph_output_collapsing_line(graph, &line);
 		return 0;
 	}
 

@@ -1227,7 +1234,7 @@ int graph_next_line(struct git_graph *graph, struct strbuf *sb)
 static void graph_padding_line(struct git_graph *graph, struct strbuf *sb)
 {
 	int i;
-	int chars_written = 0;
+	struct graph_line line = { .buf = sb, .width = 0 };
 
 	if (graph->state != GRAPH_COMMIT) {
 		graph_next_line(graph, sb);

@@ -1244,20 +1251,17 @@ static void graph_padding_line(struct git_graph *graph, struct strbuf *sb)
 	for (i = 0; i < graph->num_columns; i++) {
 		struct column *col = &graph->columns[i];
 
-		strbuf_write_column(sb, col, '|');
-		chars_written++;
+		graph_line_write_column(&line, col, '|');
 
 		if (col->commit == graph->commit && graph->num_parents > 2) {
 			int len = (graph->num_parents - 2) * 2;
-			strbuf_addchars(sb, ' ', len);
-			chars_written += len;
+			graph_line_addchars(&line, ' ', len);
 		} else {
-			strbuf_addch(sb, ' ');
-			chars_written++;
+			graph_line_addch(&line, ' ');
 		}
 	}
 
-	graph_pad_horizontally(graph, sb, chars_written);
+	graph_pad_horizontally(graph, &line);
 
 	/*
 	 * Update graph->prev_state since we have output a padding line

index c56fdec1fc..a890c9d8bb 100644
@@ -441,22 +441,31 @@ static unsigned short graph_find_commit_color(const struct git_graph *graph,
 	return graph_get_current_column_color(graph);
 }
 
+static int graph_find_new_column_by_commit(struct git_graph *graph,
+					   struct commit *commit)
+{
+	int i;
+	for (i = 0; i < graph->num_new_columns; i++) {
+		if (graph->new_columns[i].commit == commit)
+			return i;
+	}
+	return -1;
+}
+
 static void graph_insert_into_new_columns(struct git_graph *graph,
 					  struct commit *commit,
 					  int *mapping_index)
 {
-	int i;
+	int i = graph_find_new_column_by_commit(graph, commit);
 
 	/*
 	 * If the commit is already in the new_columns list, we don't need to
 	 * add it.  Just update the mapping correctly.
 	 */
-	for (i = 0; i < graph->num_new_columns; i++) {
-		if (graph->new_columns[i].commit == commit) {
-			graph->mapping[*mapping_index] = i;
-			*mapping_index += 2;
-			return;
-		}
+	if (i >= 0) {
+		graph->mapping[*mapping_index] = i;
+		*mapping_index += 2;
+		return;
 	}
 
 	/*

@@ -961,17 +970,6 @@ static void graph_output_commit_line(struct git_graph *graph, struct strbuf *sb)
 		graph_update_state(graph, GRAPH_COLLAPSING);
 }
 
-static struct column *find_new_column_by_commit(struct git_graph *graph,
-						struct commit *commit)
-{
-	int i;
-	for (i = 0; i < graph->num_new_columns; i++) {
-		if (graph->new_columns[i].commit == commit)
-			return &graph->new_columns[i];
-	}
-	return NULL;
-}
-
 static void graph_output_post_merge_line(struct git_graph *graph, struct strbuf *sb)
 {
 	int seen_this = 0;

@@ -999,20 +997,20 @@ static void graph_output_post_merge_line(struct git_graph *graph, struct strbuf
 			 * edges.
 			 */
 			struct commit_list *parents = NULL;
-			struct column *par_column;
+			int par_column;
 			seen_this = 1;
 			parents = first_interesting_parent(graph);
 			assert(parents);
-			par_column = find_new_column_by_commit(graph, parents->item);
-			assert(par_column);
+			par_column = graph_find_new_column_by_commit(graph, parents->item);
+			assert(par_column >= 0);
 
-			strbuf_write_column(sb, par_column, '|');
+			strbuf_write_column(sb, &graph->new_columns[par_column], '|');
 			for (j = 0; j < graph->num_parents - 1; j++) {
 				parents = next_interesting_parent(graph, parents);
 				assert(parents);
-				par_column = find_new_column_by_commit(graph, parents->item);
-				assert(par_column);
-				strbuf_write_column(sb, par_column, '\\');
+				par_column = graph_find_new_column_by_commit(graph, parents->item);
+				assert(par_column >= 0);
+				strbuf_write_column(sb, &graph->new_columns[par_column], '\\');
 				strbuf_addch(sb, ' ');
 			}
 		} else if (seen_this) {

index a890c9d8bb..1cd30f80e6 100644
@@ -459,23 +459,17 @@ static void graph_insert_into_new_columns(struct git_graph *graph,
 	int i = graph_find_new_column_by_commit(graph, commit);
 
 	/*
-	 * If the commit is already in the new_columns list, we don't need to
-	 * add it.  Just update the mapping correctly.
+	 * If the commit is not already in the new_columns array, then add it
+	 * and record it as being in the final column.
 	 */
-	if (i >= 0) {
-		graph->mapping[*mapping_index] = i;
-		*mapping_index += 2;
-		return;
+	if (i < 0) {
+		i = graph->num_new_columns++;
+		graph->new_columns[i].commit = commit;
+		graph->new_columns[i].color = graph_find_commit_color(graph, commit);
 	}
 
-	/*
-	 * This commit isn't already in new_columns.  Add it.
-	 */
-	graph->new_columns[graph->num_new_columns].commit = commit;
-	graph->new_columns[graph->num_new_columns].color = graph_find_commit_color(graph, commit);
-	graph->mapping[*mapping_index] = graph->num_new_columns;
+	graph->mapping[*mapping_index] = i;
 	*mapping_index += 2;
-	graph->num_new_columns++;
 }
 
 static void graph_update_width(struct git_graph *graph,

index 1cd30f80e6..a71ae5cd61 100644
@@ -453,8 +453,7 @@ static int graph_find_new_column_by_commit(struct git_graph *graph,
 }
 
 static void graph_insert_into_new_columns(struct git_graph *graph,
-					  struct commit *commit,
-					  int *mapping_index)
+					  struct commit *commit)
 {
 	int i = graph_find_new_column_by_commit(graph, commit);
 

@@ -468,50 +467,14 @@ static void graph_insert_into_new_columns(struct git_graph *graph,
 		graph->new_columns[i].color = graph_find_commit_color(graph, commit);
 	}
 
-	graph->mapping[*mapping_index] = i;
-	*mapping_index += 2;
-}
-
-static void graph_update_width(struct git_graph *graph,
-			       int is_commit_in_existing_columns)
-{
-	/*
-	 * Compute the width needed to display the graph for this commit.
-	 * This is the maximum width needed for any row.  All other rows
-	 * will be padded to this width.
-	 *
-	 * Compute the number of columns in the widest row:
-	 * Count each existing column (graph->num_columns), and each new
-	 * column added by this commit.
-	 */
-	int max_cols = graph->num_columns + graph->num_parents;
-
-	/*
-	 * Even if the current commit has no parents to be printed, it
-	 * still takes up a column for itself.
-	 */
-	if (graph->num_parents < 1)
-		max_cols++;
-
-	/*
-	 * We added a column for the current commit as part of
-	 * graph->num_parents.  If the current commit was already in
-	 * graph->columns, then we have double counted it.
-	 */
-	if (is_commit_in_existing_columns)
-		max_cols--;
-
-	/*
-	 * Each column takes up 2 spaces
-	 */
-	graph->width = max_cols * 2;
+	graph->mapping[graph->width] = i;
+	graph->width += 2;
 }
 
 static void graph_update_columns(struct git_graph *graph)
 {
 	struct commit_list *parent;
 	int max_new_columns;
-	int mapping_idx;
 	int i, seen_this, is_commit_in_columns;
 
 	/*

@@ -544,6 +507,8 @@ static void graph_update_columns(struct git_graph *graph)
 	for (i = 0; i < graph->mapping_size; i++)
 		graph->mapping[i] = -1;
 
+	graph->width = 0;
+
 	/*
 	 * Populate graph->new_columns and graph->mapping
 	 *

@@ -554,7 +519,6 @@ static void graph_update_columns(struct git_graph *graph)
 	 * supposed to end up after the collapsing is performed.
 	 */
 	seen_this = 0;
-	mapping_idx = 0;
 	is_commit_in_columns = 1;
 	for (i = 0; i <= graph->num_columns; i++) {
 		struct commit *col_commit;

@@ -568,7 +532,6 @@ static void graph_update_columns(struct git_graph *graph)
 		}
 
 		if (col_commit == graph->commit) {
-			int old_mapping_idx = mapping_idx;
 			seen_this = 1;
 			graph->commit_index = i;
 			for (parent = first_interesting_parent(graph);

@@ -583,21 +546,18 @@ static void graph_update_columns(struct git_graph *graph)
 				    !is_commit_in_columns) {
 					graph_increment_column_color(graph);
 				}
-				graph_insert_into_new_columns(graph,
-							      parent->item,
-							      &mapping_idx);
+				graph_insert_into_new_columns(graph, parent->item);
 			}
 			/*
-			 * We always need to increment mapping_idx by at
+			 * We always need to increment graph->width by at
 			 * least 2, even if it has no interesting parents.
 			 * The current commit always takes up at least 2
 			 * spaces.
 			 */
-			if (mapping_idx == old_mapping_idx)
-				mapping_idx += 2;
+			if (graph->num_parents == 0)
+				graph->width += 2;
 		} else {
-			graph_insert_into_new_columns(graph, col_commit,
-						      &mapping_idx);
+			graph_insert_into_new_columns(graph, col_commit);
 		}
 	}
 

@@ -607,11 +567,6 @@ static void graph_update_columns(struct git_graph *graph)
 	while (graph->mapping_size > 1 &&
 	       graph->mapping[graph->mapping_size - 1] < 0)
 		graph->mapping_size--;
-
-	/*
-	 * Compute graph->width for this commit
-	 */
-	graph_update_width(graph, is_commit_in_columns);
 }
 
 void graph_update(struct git_graph *graph, struct commit *commit)

index a71ae5cd61..98e8777db4 100644
@@ -569,6 +569,12 @@ static void graph_update_columns(struct git_graph *graph)
 		graph->mapping_size--;
 }
 
+static int graph_needs_pre_commit_line(struct git_graph *graph)
+{
+	return graph->num_parents >= 3 &&
+	       graph->commit_index < (graph->num_columns - 1);
+}
+
 void graph_update(struct git_graph *graph, struct commit *commit)
 {
 	struct commit_list *parent;

@@ -624,8 +630,7 @@ void graph_update(struct git_graph *graph, struct commit *commit)
 	 */
 	if (graph->state != GRAPH_PADDING)
 		graph->state = GRAPH_SKIP;
-	else if (graph->num_parents >= 3 &&
-		 graph->commit_index < (graph->num_columns - 1))
+	else if (graph_needs_pre_commit_line(graph))
 		graph->state = GRAPH_PRE_COMMIT;
 	else
 		graph->state = GRAPH_COMMIT;

@@ -708,8 +713,7 @@ static void graph_output_skip_line(struct git_graph *graph, struct strbuf *sb)
 	strbuf_addstr(sb, "...");
 	graph_pad_horizontally(graph, sb);
 
-	if (graph->num_parents >= 3 &&
-	    graph->commit_index < (graph->num_columns - 1))
+	if (graph_needs_pre_commit_line(graph))
 		graph_update_state(graph, GRAPH_PRE_COMMIT);
 	else
 		graph_update_state(graph, GRAPH_COMMIT);

index 98e8777db4..9136173e03 100644
@@ -183,6 +183,20 @@ struct git_graph {
 	 * previous commit.
 	 */
 	int prev_commit_index;
+	/*
+	 * Which layout variant to use to display merge commits. If the
+	 * commit's first parent is known to be in a column to the left of the
+	 * merge, then this value is 0 and we use the layout on the left.
+	 * Otherwise, the value is 1 and the layout on the right is used. This
+	 * field tells us how many columns the first parent occupies.
+	 *
+	 * 		0)			1)
+	 *
+	 * 		| | | *-.		| | *---.
+	 * 		| |_|/|\ \		| | |\ \ \
+	 * 		|/| | | | |		| | | | | *
+	 */
+	int merge_layout;
 	/*
 	 * The maximum number of columns that can be stored in the columns
 	 * and new_columns arrays.  This is also half the number of entries

@@ -294,6 +308,7 @@ struct git_graph *graph_init(struct rev_info *opt)
 	graph->prev_state = GRAPH_PADDING;
 	graph->commit_index = 0;
 	graph->prev_commit_index = 0;
+	graph->merge_layout = 0;
 	graph->num_columns = 0;
 	graph->num_new_columns = 0;
 	graph->mapping_size = 0;

@@ -453,9 +468,11 @@ static int graph_find_new_column_by_commit(struct git_graph *graph,
 }
 
 static void graph_insert_into_new_columns(struct git_graph *graph,
-					  struct commit *commit)
+					  struct commit *commit,
+					  int idx)
 {
 	int i = graph_find_new_column_by_commit(graph, commit);
+	int mapping_idx;
 
 	/*
 	 * If the commit is not already in the new_columns array, then add it

@@ -467,8 +484,26 @@ static void graph_insert_into_new_columns(struct git_graph *graph,
 		graph->new_columns[i].color = graph_find_commit_color(graph, commit);
 	}
 
-	graph->mapping[graph->width] = i;
-	graph->width += 2;
+	if (graph->num_parents > 1 && idx > -1 && graph->merge_layout == -1) {
+		/*
+		 * If this is the first parent of a merge, choose a layout for
+		 * the merge line based on whether the parent appears in a
+		 * column to the left of the merge
+		 */
+		int dist, shift;
+
+		dist = idx - i;
+		shift = (dist > 1) ? 2 * dist - 3 : 1;
+
+		graph->merge_layout = (dist > 0) ? 0 : 1;
+		mapping_idx = graph->width + (graph->merge_layout - 1) * shift;
+		graph->width += 2 * graph->merge_layout;
+	} else {
+		mapping_idx = graph->width;
+		graph->width += 2;
+	}
+
+	graph->mapping[mapping_idx] = i;
 }
 
 static void graph_update_columns(struct git_graph *graph)

@@ -534,6 +569,7 @@ static void graph_update_columns(struct git_graph *graph)
 		if (col_commit == graph->commit) {
 			seen_this = 1;
 			graph->commit_index = i;
+			graph->merge_layout = -1;
 			for (parent = first_interesting_parent(graph);
 			     parent;
 			     parent = next_interesting_parent(graph, parent)) {

@@ -546,7 +582,7 @@ static void graph_update_columns(struct git_graph *graph)
 				    !is_commit_in_columns) {
 					graph_increment_column_color(graph);
 				}
-				graph_insert_into_new_columns(graph, parent->item);
+				graph_insert_into_new_columns(graph, parent->item, i);
 			}
 			/*
 			 * We always need to increment graph->width by at

@@ -557,7 +593,7 @@ static void graph_update_columns(struct git_graph *graph)
 			if (graph->num_parents == 0)
 				graph->width += 2;
 		} else {
-			graph_insert_into_new_columns(graph, col_commit);
+			graph_insert_into_new_columns(graph, col_commit, -1);
 		}
 	}
 

@@ -569,10 +605,36 @@ static void graph_update_columns(struct git_graph *graph)
 		graph->mapping_size--;
 }
 
+static int graph_num_expansion_rows(struct git_graph *graph)
+{
+	/*
+	 * Normally, we need two expansion rows for each dashed parent line from
+	 * an octopus merge:
+	 *
+	 * 		| *
+	 * 		| |\
+	 * 		| | \
+	 * 		| |  \
+	 * 		| *-. \
+	 * 		| |\ \ \
+	 *
+	 * If the merge is skewed to the left, then its parents occupy one less
+	 * column, and we don't need as many expansion rows to route around it;
+	 * in some cases that means we don't need any expansion rows at all:
+	 *
+	 * 		| *
+	 * 		| |\
+	 * 		| * \
+	 * 		|/|\ \
+	 */
+	return (graph->num_parents + graph->merge_layout - 3) * 2;
+}
+
 static int graph_needs_pre_commit_line(struct git_graph *graph)
 {
 	return graph->num_parents >= 3 &&
-	       graph->commit_index < (graph->num_columns - 1);
+	       graph->commit_index < (graph->num_columns - 1) &&
+	       graph->expansion_row < graph_num_expansion_rows(graph);
 }
 
 void graph_update(struct git_graph *graph, struct commit *commit)

@@ -722,7 +784,6 @@ static void graph_output_skip_line(struct git_graph *graph, struct strbuf *sb)
 static void graph_output_pre_commit_line(struct git_graph *graph,
 					 struct strbuf *sb)
 {
-	int num_expansion_rows;
 	int i, seen_this;
 
 	/*

@@ -733,14 +794,13 @@ static void graph_output_pre_commit_line(struct git_graph *graph,
 	 * We need 2 extra rows for every parent over 2.
 	 */
 	assert(graph->num_parents >= 3);
-	num_expansion_rows = (graph->num_parents - 2) * 2;
 
 	/*
 	 * graph->expansion_row tracks the current expansion row we are on.
 	 * It should be in the range [0, num_expansion_rows - 1]
 	 */
 	assert(0 <= graph->expansion_row &&
-	       graph->expansion_row < num_expansion_rows);
+	       graph->expansion_row < graph_num_expansion_rows(graph));
 
 	/*
 	 * Output the row

@@ -782,7 +842,7 @@ static void graph_output_pre_commit_line(struct git_graph *graph,
 	 * and move to state GRAPH_COMMIT if necessary
 	 */
 	graph->expansion_row++;
-	if (graph->expansion_row >= num_expansion_rows)
+	if (!graph_needs_pre_commit_line(graph))
 		graph_update_state(graph, GRAPH_COMMIT);
 }
 

@@ -820,7 +880,7 @@ static void graph_draw_octopus_merge(struct git_graph *graph, struct strbuf *sb)
 	 * x 0 1 2 3
 	 *
 	 */
-	const int dashless_parents = 2;
+	const int dashless_parents = 3 - graph->merge_layout;
 	int dashful_parents = graph->num_parents - dashless_parents;
 
 	/*

@@ -828,9 +888,9 @@ static void graph_draw_octopus_merge(struct git_graph *graph, struct strbuf *sb)
 	 * above) but sometimes the first parent goes into an existing column,
 	 * like this:
 	 *
-	 * | *---.
-	 * | |\ \ \
-	 * |/ / / /
+	 * | *-.
+	 * |/|\ \
+	 * | | | |
 	 * x 0 1 2
 	 *
 	 * In which case the number of parents will be one greater than the

@@ -923,10 +983,15 @@ static void graph_output_commit_line(struct git_graph *graph, struct strbuf *sb)
 		graph_update_state(graph, GRAPH_COLLAPSING);
 }
 
+const char merge_chars[] = {'/', '|', '\\'};
+
 static void graph_output_post_merge_line(struct git_graph *graph, struct strbuf *sb)
 {
 	int seen_this = 0;
-	int i, j;
+	int i;
+
+	struct commit_list *first_parent = first_interesting_parent(graph);
+	int seen_parent = 0;
 
 	/*
 	 * Output the post-merge row

@@ -949,30 +1014,34 @@ static void graph_output_post_merge_line(struct git_graph *graph, struct strbuf
 			 * new_columns and use those to format the
 			 * edges.
 			 */
-			struct commit_list *parents = NULL;
+			struct commit_list *parents = first_parent;
 			int par_column;
+			int idx = graph->merge_layout;
+			char c;
 			seen_this = 1;
-			parents = first_interesting_parent(graph);
-			assert(parents);
-			par_column = graph_find_new_column_by_commit(graph, parents->item);
-			assert(par_column >= 0);
-
-			strbuf_write_column(sb, &graph->new_columns[par_column], '|');
-			for (j = 0; j < graph->num_parents - 1; j++) {
-				parents = next_interesting_parent(graph, parents);
-				assert(parents);
+
+			for (; parents; parents = next_interesting_parent(graph, parents)) {
 				par_column = graph_find_new_column_by_commit(graph, parents->item);
 				assert(par_column >= 0);
-				strbuf_write_column(sb, &graph->new_columns[par_column], '\\');
-				strbuf_addch(sb, ' ');
+
+				c = merge_chars[idx];
+				strbuf_write_column(sb, &graph->new_columns[par_column], c);
+				if (idx == 2)
+					strbuf_addch(sb, ' ');
+				else
+					idx++;
 			}
 		} else if (seen_this) {
 			strbuf_write_column(sb, col, '\\');
 			strbuf_addch(sb, ' ');
 		} else {
 			strbuf_write_column(sb, col, '|');
-			strbuf_addch(sb, ' ');
+			if (graph->merge_layout != 0 || i != graph->commit_index - 1)
+				strbuf_addch(sb, seen_parent ? '_' : ' ');
 		}
+
+		if (col_commit == first_parent->item)
+			seen_parent = 1;
 	}
 
 	graph_pad_horizontally(graph, sb);